Figure 2

Microscopic lesions (HE staining) and viral replication (IHC staining) at 3 dpi in several organs obtained from chicken breeds experimentally inoculated with H7N1 and H5N8 HPAIVs. Myocardium A, B (H7N1 infected), K, L (H5N8 infected): multifocal necrosis of myocardiocytes with inflammatory infiltrate (A, K) and NP-positive myocardiocytes and inflammatory cells (B, L). CNS C, D (H7N1 infected) M, N (H5N8 infected): multifocal areas of necrosis in cerebral hemispheres (C, M), widespread NP-positive neurons and glial cells (D, N). Pancreas E, F (H7N1 infected), O, P (H5N8 infected): diffuse area of necrosis in pancreatic acinar cells (E, O) associated with widespread NP-positive cells in necrotic areas and surrounding acinar pancreatic cells (F, P). Lung G, H (H7N1 infected), Q, R (H5N8 infected): mild increase of cellularity (mixed inflammatory cells) in air capillaries interstitium (G) and few NP-positive inflammatory cells (H). Severe increase of increase of cellularity in air capillaries interstitium, focal areas of necrosis in pneumocytes, microthrombi and diffuse oedema (Q), widespread NP-positive cells in inflammatory cells, endothelial cells and air capillary cells (R). Spleen I, J (H7N1 infected), S, T (H5N8 infected): non-apparent lesions (I) and few NP-positive lymphoid-cells (J). Areas of necrosis with mixed inflammatory cell infiltration (S), widespread NP-cells in inflammatory and endothelial cells (T).